Nothing to eat and nowhere to sit down. More bad news for polar bears November 19 2015, 0 Comments

Changes in the sea ice season mean polar bears can’t get to the food that is their natural prey--and now it seems clear they can’t thrive on the food they are able to forage on land.

Dampening the hopes of those who believed polar bears could readily adapt to a land-based diet, a new study from a team of scientists led by the US Geological Survey concludes that polar bears stranded on land are not getting enough food, and what food they are getting is not suited to their biological needs (http://tinyurl.com/pbeardietUSGS).

These pale giants are shaped, sized, insulated, colored--in every way supremely adapted to life on ice, where they hunt, mate, and give birth. Their bulk helps them retain body heat. An insulating layer of fat beneath their skin helps preserve warmth at the core. Their diet--a nearly all-fat diet of super-high-calorie seal blubber--is key to the energy they need to survive (http://tinyurl.com/pbearintlFAQ). Polar bears are apex predators, superb hunters, patient and skilled--but unless they can get out on the pack ice, they cannot hunt for seals.

Stranded on land, the polar bears eat whatever they can get, including plants, birds, berries and eggs. They eat trash. Men’s Journal reports that residents of the Inuit town of Arviat, in northern Canada, finally ceded control of the town dump to polar bears looking for food. Some days there are as many as eight hungry bears poking around the Arviat dump (http://tinyurl.com/ArviatpbearsMJ)

These are big animals--according to Polar Bears International, an adult male polar bear can weigh 1300 pounds--and they have high energy requirements. The new study describes the polar bear’s ordinary blubber-rich diet as “energetically dense” to a striking degree. Now, say the scientists, the bears are keeping alive by eating plants they can ill digest, and “high-protein, low-fat animals.” Too little nutrition, too little fat to fuel energy, and quantities too meager to quiet the demands of hunger (http://tinyurl.com/pbeardietUSGS).